91. Have you saw someone ___________ (ski) before?

90. Have you finished ___________ (read) the book?

89. Who is doing well in ___________ (describe) things?

88. You'd better try to give up ___________ (smoke). It's too bad to your health.

87. We ___________ never ___________ (be) to Hawaii.

86. Miss Green ___________(be) in China for 6 years.

85. ___________you ever ___________(ride) a horse before?

84. We ___________ (not see) each other since he ___________ (leave) here.

83. Our teacher told us time ___________ (be) life.

82. These exercises must ___________ (do) by yourself.